Possible Transmission Problem?
 

My wife has a 2013 RDX with approximately 90,000 miles. She reports that approximately two weeks ago there was a flapping sound that increased in volume at or around the left wheel. She indicated that it lasted for a couple of miles and then went away. Today, I was in the car with her and heard what she was talking about. It was quite loud increasing in volume with speed. At some point we stopped the car and I had her turn the wheels in both directions and could not see anything that looked unusual with the wheel or brake assembly. Initially I thought that it could be related to a joint or bearing issue, but from my experience working on cars that that sound didn’t match. Wonder if it could be after she drives at bit at some point that it shifts into gear and the sound goes away? Took it to a transmission shop and they told me they would have to hear the sound to figure out what’s wrong. I feel a bit stuck as I would like to have more information to go on if she’s going to be driving the car. Any recommendations would be appreciated. Thanks.